These beams have always been made in one piece, with an uninterrupted metal reinforcement, but not without disadvantages and inconveniences. The beams can be of various lengths and sections and with different slopes. Their construction in one piece requires formwork which is particularly bulky, not only because of its length but also because of its height, especially for beams with a steep slope. The handling of these beams is extremely difficult due to their dimensions and their relative weight. Then the transport of these whole beams, in particular those which are long, always presents problems, beyond being very expensive, especially when it is necessary to resort to exceptional transport and/or there is a need to travel on narrow or mountainous roads
All these difficulties mean that up to now beams have been constructed below a certain dimension, in order not to aggravate the problems of bulk, transport, etc., even if the demand for certain installations would be for longer beams.
On the other hand, a simple subdivision of the said beams into two parts would make the handling and transporting simpler, but would bring with it problems of joining the two parts and of maintaining the strength and static nature of the beams when in use and under load.